Conventional composite bellows seal assemblies are often configured to include an insert, such as a carbon graphite insert, that is pressed or shrunk into a front seal ring shell cavity. With some applications, an epoxy or bonding agent is added to the back wall interface of the shell and insert to help prevent system fluid pressure unfavorably encroaching upon and affecting the interface. In some conventional designs, aside from a bonding agent and/or friction between components, there may be no additional mechanical features to restrain an insert from blowing out during a high-pressure condition.
Moreover, it can be challenging if the back wall of the insert becomes pressurized with, or subject to, significant system pressure. That is, if the system pressure invades the interface at too significant a level, there can be an increased possibility that the pressure will work to urge the insert out of the shell which, in some instances, could result in a blow out of the insert and possibly even sealing system failure. If an insert is solely press fit, without bonding, a tremendous amount of interference or friction can be needed to hold it in place in operation.
Additionally, it can also be desirable to provide assemblies with an overall reduction in weight. With dynamic operation contemplated, a seal ring assembly seal face may be designed to be in contact with, or in close proximity to, a rotating rotor, even during slight axial excursions or run out—commonly referred to as “tracking.” With tracking, it can be desirable for there to be a reduction in mass, as a reduction in mass can lead to better stability and component tracking. Therefore, among other things, it can be desirable to provide a seal and assembly with a reduction in weight/mass.
Among other things, it can be a challenge to provide improved seals and sealing assemblies that address some or all of the aforementioned challenges.